Carbon anode



May 23, 1939. J. A. ZITZLER CARBON ANODE Original Filed June 3, 1932 Patented May 23, 1939 UNITED STATES PATENT OFFIQE CARBON ANODE John Augusta Zitzler, St. Marys, Pa., assignor to Speer Carbon Company, a corporation of Pennsylvania 17 Claims.

This invention relates to carbon anodes; and it relates to a hollow cylindrical type of carbon anode, more particularly one having the form of a hollow oblate cylinder, made of one integral piece of carbon, and to an electron device, such as a vacuum tube, comprising such an anode in operative assembly with filament and grid elements.

The present invention is a division of copending application Serial No. 615,112, filed June 3, 1932.

Prior to the present invention, it was customary to employ a metal such as molybdenum in manufacturing plates or anodes for vacuum tubes, especially tubes of the large transmitting types. Besides being undesirably expensive, m0- lybdenum could be employed for such anodes only by constructing the anode of a plurality of pieces or members fastened together to give an anode structure of the required shape or contour. Furthermore, such built-up anodes, whether made of molybdenum or other material, were for various reasons not altogether satisfactory in service According to the present invention, the difficulties and disadvantages heretofore encountered are overcome by making an anode in the form of a unitary hollow cylinder, more, particularly a flattened or oblate cylinder, from one integral piece of suitable carbon material, such unitary construction including provision whereby the anode can be readily mounted on supporting means in a vacuum tube and held in place without any clamps or binding posts being required. Electrographite, that is, graphite made by electric heating to a very high temperature, is a particularly desirable kind of carbon material to employ in the practice of the invention. Anodes constructed in accordance with the principles of the invention are highly satisfactory, being particularly well adapted for use in large transmitting types of vacuum tubes.

For a further understanding of the invention, one desirable practical embodiment thereof will now be described in detail by way of a concrete illustrativeexample, reference being had to the accompanying drawing wherein,

Fig, 1 is a perspective view of an oblate hollow cylindrical unitary carbon anode within the scope of the invention, and

Fig. 2 is a section on the plane 22 of Fig. 1.

Referring to the drawing, the anode shown is accurately machined to the proper form and dimensions from one piece or block of electrographite. In the oblate hollow cylindrical form here illustrated, the anode comprises two opposite parallel side portions l0 joined by two opposite curved end portions l l, and is provided with 1ongitudinally extending flanges 12 which project outwardly or laterally from said flat side portions, these flanges being adapted to accommodate anode-supporting means. In the present instance, each flange is provided with a channel or bore l3 extending through its entire length, these channels or holes being adapted to receive the usual supporting wires or standards by which the anode is held in proper position in the electron device assembly. Each hole 13 is formed preferably by drilling into each flange from the opposite ends thereof. For example, as here shown, holes are drilled approximately half way from each end of the flange, meeting at M, as shown in Fig. 2. It is not necessary that these oppositely drilled holes shall exactly coincide or be in per feet alinement at this point of meeting or junction; indeed it is preferable to have their axes slightly offset or out of line at the junction point I4 and then to start a drill through the holes or bores to drill out, the section where they do not quite coincide, thus properly connecting them.

When the anode is mounted on the supporting standards, such standards are forced to bend slightly where the holes are out of line, and thus a good firm contact is made with said standards whereby good electrical contact is made, microphonic noises are prevented, and the anode is firmly held in proper position in the vacuum tube (not shown). In place of the internal bores or holes 13, a groove or recess may be machined in the outer face of each flange to receive or be engaged by the supporting wires or standards.

It will accordingly be seen that the provision included in the hollow cylindrical or tubular shell type of unitary carbon electrode to which the invention is directed may be described as constituted by extensions, specifically flange means, along the length of the tubular shell, the extensions being provided with openings adapted to accommodate supporting means.

The machining of the graphite block to pro vide the described external contour of the block is accomplished by grinding operations unnecessary to describe in detail here. In hollowing out the anode to provide the chamber enclosed by the side and end portions or walls In and l 1, holes may be drilled through the carbon block at points I4, 15, and a routing tool employed to cut out the material between said holes; or, if desired, the rest of the channel or chamber may be completed by routing out the rest of the material after drilling but one such hole.

A unitary carbon anode produced as herein described has its walls accurately formed to give the required spacing when the anode is assembled in a vacuum tube with cooperating filament and grid elements.

Having described my invention, what I claim is:

1. A vacuum tube anode consisting of a hollow cylinder and integral flanges extending outwardly from the walls of said cylinder, said flanges having holes extending longitudinally thereof to receive supporting wires, said cylinder and said flanges being one integral piece of carbon.

2. A carbon anode adapted to be held by supporting wires consisting of a hollow cylinder and flanges extending outwardly from the walls of said cylinder, each of said flanges having connecting holes extending from each end longitudinally thereof and slightly out of line with each other to receive said supporting wires and fllrmly contact therewith.

3. A carbon anode adapted to be held by supporting wires consisting of a hollow cylinder and flanges extending outwardly from the walls of said cylinder, each of said flanges having connecting holes extending from each end longitudinally thereof and slightly out of line with each other to receive said supporting wires and firmly contact therewith, said cylinder and said flanges being one integral piece of carbon.

4. A unitary carbon anode consisting of a hollow cylinder provided laterally with longitudinally extending flange means adapted to accommodate supporting means, the entire anode being made of one integral piece of carbon and having its walls accurately formed to required dimensions and parallel to the axis of the cylinder.

5. A unitary carbon anode consisting of an oblate hollow cylinder comprising two parallel fiat side portions joined by two opposite curved end portions and being provided with longitudinally extending flanges which project outwardly from said flat portions and have openings therein adapted to accommodate supporting means, said anode consisting of one integral piece of carbon and having its walls accurately formed to required dimensions.

6. A unitary carbon anode consisting of an oblate hollow cylinder comprising two parallel flat side portions joined by two opposite curved end portions and being provided with longitudinally extending flanges which project outwardly from said flat portions and each of which has a hole extending longitudinally therethrough and parallel to the axis of the cylinder, said holes being adapted to accommodate supporting standards, said anode consisting of one integral piece of carbon and having its walls accurately formed to required dimensions and parallel to the axis of the cylinder,

'7. An electron discharge device comprising a vacuum tube within which are assembled in operative relation to each other a filament, a grid, and an oblate hollow cylindrical carbon anode, said anode comprising two parallel fiat side portions joined by two opposite curved end portions and being provided with longitudinally extending flanges which project outwardly from said flat side portions and have support-receiving openings therein, and supporting wires engaging said openings, said anode consisting of one integral piece of carbon and having its walls accurately formed to give the required spacing thereof with respect to said filament and grid.

8. In a vacuum tube of the transmitting type, the combination of a filament, a grid and a hollow cylindrical anode, assembled and supported in operative relation to each other, said anode consisting of one integral piece of electrographite.

9. In a vacuum tube, the combination of a filament, a grid and an electrographite anode, assembled and supported in operative relation to each other, said anode consisting of-one integral piece of electrographite in the form of a hollow cylinder having laterally disposed support-engaging provision adapted to accommodate supporting means.

10. An electron discharge device comprising, in combination, a filament, a grid, and an electrographite anode, assembled and supported in operative relation to each other, said anode consisting of one integral piece of electrographite in the form of an oblate hollow cylinder having its Walls accurately dimensioned and parallel to the axis of the cylinder.

11. An electron discharge device comprising, in combination, a filament, a grid, and an electrographite anode, assembled and supported in operative relation to each other, said anode consisting of one integral piece of electrographite in the form of a hollow cylinder comprising two parallel flat side portions joined by two opposite curved end portions and being provided with longitudinally extending flanges which project outwardly from said flat side portions and have support-receiving openings therein, and supporting standards engaging said openings, the walls of the anode being accurately formed to give the required spacing thereof with respect to said filament and grid.

12. An electrode consisting of one integral piece of electrographite in the form of a hollow cylinder having laterally disposed support-engaging provision adapted to accommodate supporting means.

13. An electrode consisting of one integral piece of electrographite in the form of a hollow cylinder having laterally projecting flange means extending longitudinally thereof and adapted to accommodate supporting means.

14. An electrographite anode consisting of an oblate hollow cylinder and flanges extending outwardly from the walls of said cylinder, said flanges having holes extending longitudinally thereof toreceive supporting wires, said cylinder and said flanges being one integral piece of electrographite.

15. An electrode comprising one integral piece of electrographite in the form of a tubular shell having extensions along the length thereof, said extensions having openings therein adapted to accommodate supporting means.

16. A carbon anode consisting of an oblate hollow cylinder and flanges extending outwardly from the wall of the said cylinder, said flanges having holes extending longitudinally thereof to receive supporting wires, said cylinder and said flanges being one integral piece of carbon.

17. An electrode comprising a single composite unit of graphite in the form of a tubular shell having extensions along the length thereof, said extensions having openings therein adapted to accommodate supporting means JOHN AUGUSTA ZITZLER. 

